Reaction of Substituted 1,3,2-Dioxaborolanes with Acetonitrile

Reaction of 2-alkyl- and 2-alkoxy-4,4,5,5-tetramethyl- and 4,5-diphenyl-1,3,2-dioxaborolanes with acetonitrile leads to the corresponding 2-oxazolines. Their yield is determined by the nature of the substituent on the boron atom in the molecule of the starting cyclic boric ester. The results obtained are consistent with calculated values of the relative stability for the intermediate ions (AM1).     

Reactions of cyclic α-methoxy nitrones with nucleophilic reagents

Reactions of cyclic -methoxy nitrones, which are derivatives of imidazole or dihydroimidazole N-oxides, with amines, KOH, or KSH result in the replacement of the MeO group to form cyclic -amino nitrones, hydroxamic acids, or thiohydroxamic acids, respectively. Analogous reactions occur with C-nucleophiles.     

Novel four-membered silicon-phosphorus-containing heterocycles

Four-membered heterocycles have been prepared by the reaction of (methyldichlorosilyl)- and (dimethylchlorosilyl)methyldichlorophosphines with primary aliphatic amines: 1,2³,4-azaphosphasiletidines and acyclic (methylaminosilyl)methyldiamidophosphonites. The latter eliminate primary amines on heatingin vacuo to give 1,2³,4-azaphosphasiletidines. The structures of the compounds thus obtained have been studied by³¹P,²⁹Si,¹H, and¹³C NMR.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 990–991, May, 1993.     

Interaction of fluoroalkyl-containing β-diketones with amines

The composition of products of the interaction of asymmetric fluoroalkyl-containing -diketones with amines was studied. Mixtures of regioisomeric -aminovinylketones and products of cleavage and secondary condensation are formed, depending on the temperature, the solvent, the nature of the fluorinated and nonfluorinated substituents in the -diketone, and the basicity of the amine. The major product is a -aminovinylketone in which the NH₂ group is removed from the fluoroalkyl substituent. No -aminovinylimines, products of condensation involving two electrophilic centers, were observed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2278–2284, September, 1996.     

Synthesis of Co3(CO)7(μ-η3-Allyl)(μ3-X) Complexes (X=S, Se) and Structure of the Selenium Derivative

The complexes Co₃(CO)₉( ₃-X) (X=S, Se) can be reduced to the corresponding anionic species [Co₃(CO)₉( ₃-X)]^–, which react with allyl bromide to give Co₃(CO)₇(- ³-C₃H₅)( ₃-X) (X=S, Se). These are the first two cobalt complexes containing the bridging - ³-allyl ligand. The structure of the selenium complex was determined by X-ray crystallography. Crystal data for Co₃(CO)₇(- ³-C₃H₅)( ₃-Se) are as follows: space group P2₁/c, a=9.051(2) Å, b=8.102(2) Å, c=21.27(4) Å, =93.82(3)°, Z=4, and R=0.0565 for 2491 observed reflections.     

Dinitramide and its salts

The dinitramide anion shows ambident properties. Its reactions with alkylating reagents give rise toN- orO-alkylated products or their mixtures. The reactions of alkylated products with bases were studied.For the previous communication, see V. A. Shlyapochnikov, G. I. Oleneva, N. O. Cherskaya, O. A. Luk'yanov, V. P. Gorelik, O. V. Anikin, and V. A. Tartakovsky,Izv. Akad. Nauk, Ser. Khim., 1994, 1610 [Russ. Chem. Bull., 1994,43, No. 11 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1775–1778, October, 1994.     

α-(N-Sulfonylamino)alkylphosphonates

-(N-Sulfonylamino)alkyl phosphites, which are intermediate products in the reactions of the corresponding hydroxy derivatives with diethyl phosphorochloridite, undergo in situ phosphorotropic rearrangement to give C-phosphorylated products.     

Reactions of β-aminopropionic acid N"-acylhydrazides with carbonyl compounds

The reactions of -aminopropionic acid N"-acylhydrazides with aromatic and heterocyclic aldehydes and acetone afford compounds that exist in solutions predominantly as mixtures of 2-substituted 3-acylaminotetrahydropyrimidin-4-ones (ATHP) and tautomeric Schiff"s bases. These compounds in the crystalline state probably have structures of ATHP. The ratio of tautomers depends on the type of substituent in the aromatic ring and solvent. The reactions of 2-aryl-3-benzamidotetrahydropyrimidin-4-ones with carboxylic or sulfonic acid chlorides afford derivatives of 1-acyl- and 1-tosyl-3-benzamidotetrahydropyrimidin-4-ones.     

Zum Verhalten von Orthocarbonsäureestern gegenüber Trimethylsilylchlorid, -azid und -cyanid

The reaction of cyclic orthoesters of cyclohexanes and steroides with trimethylsilylchloride,-azide and-cyanide points out novel, mechanistic aspects as well as remarkable preparative possibilities. The mixture1 a/1 b of theexo/endo stereoisomers of the cyclic orthoesters derived fromcis-cyclohexane-1,2-diol was transformed to the expected 1-yl-ethanoate3 of thetrans-2-chlorocyclohexan-1-ol. In contrast the reaction of1 a/1 b with trimethylsilylazide and trimethylsilycyanide yields the correspondingexo/endo mixtures of2 a/2 b and2 c/2 d resp. The cyclic orthoester oftrans-cyclohexan-1,2-diol (4) similarily affords the products5 a and5 b, whereas transformation with trimethylsilylchloride 1-yl-ethanoate of thecis-2-chlorocyclohexan-1-ol could not be achieved for steric reasons. The cyclic orthoesters6 a/6 b ofcis-cyclohex-1-en-3,4-diol are converted regio- and stereospecifically to the products7 and9 using trimethylsilychloride and- azide, whereas theexo/endo mixture8 a/8 b of the corresponding cyclic orthoester derivative is formed with trimethylsilylcyanide. The orthoesters10 a/10 b prepared from 2,3-cis-dihydroxycyclohexanone-1 give thetrans-2-chloro-3-oxocyclohexyl-ethanoate (11) and its elimination product12. In analogy13 is produced by treating10 a/10 b with trimethylsilylacetate. Theexo/endo mixture of cyclic esters14 a/14 b 3-cholestan-2,3-diol gives the corresponding mixture15 a/15 b when treated with trimethylsilycyanide. Reaction of Trimethylsilychloride with14 a/14 b affords mainly thetrans-diequatorial product17 a and only small amounts of thetrans-diaxial product17b. In contrast the mixture18a/18b yields exclusively thetrans-diaxials product20 on reaction with trimethylsilylchloride. With trimethylsilcyanide the cyclic orthoester derivative21 a/21 b is formed. The cyclic esters22 a/22 b of 1,2-dihydroxychloestanone-3 react with trimethylsilylchloride to give the easily explicable elimination product23 and the rearranged 3-methoxy-cholesten-3-one-2 (24). The corresponding cyclic orthesters25 a/25 b of 1,2-dihydroxy-3-oxo-androstans-17-yl-ethanoate in a similar way afford the elimination product26 to a small extent and the rearranged 3-methoxy-2-oxo-androstan-17-yl-ethanoate (27) as the main product.

Herrn Prof. Dr.H. Pommer mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Zum Reaktionsmechanismus von Glutaraldehyd mit Proteinen

The interaction of glutaraldehyde with model aliphatic amines was studied in order to understand the crosslinking reaction of glutaraldehyde with proteins. The reaction in organic solvents gave N-alkyl-1,4-dihydropyridines and N,N-dialkyl-1,5-diiminopentanes. The isolated products are new or were previously described by us for the first time¹. Hydration of the reaction products led to stable N-alkylpiperidines and N,N-dialkyl-1,5-diaminopentanes. In aqueous solution the reaction depends on thepH: at apH above 7, N-alkyl-1,4-dihydropyridines and at apH below 7, polymers were obtained. For the crosslinking reaction of proteins with glutaraldehyde the following mechanism is proposed: Monomeric glutaraldehyde reacts with the protein to give intermediate N-alkyl-2,6-dihydroxypiperidines. Intramolecular dehydration leads to the corresponding N-alkyl-1,4-dihydropyridines. Condensation of the cyclic monohydrate of glutaraldehyde and N-alkyl-2,6-dihydroxypiperidines gives linear polymeric crosslinks containing -oxo-N-alkylpiperidine units.

Lubig R., Dissertation, RWTH Aachen, 1974.     

Tetracyclische Imidazole

2-(Phenacyl)-tetrahydro--carboline (2) was transformed to theE/Z-oximes3 and4 and the isolated species cyclodehydrogenated to the nitrone5 and oxadiazine6. These compounds were dehydrated in acidic medium to the imidazole9.

     

Reactions of N-(2-chloroacetyl)-α-amino acids with 3-cyanopyridine-2(1H)-thiones. New promising route to 3,4-dihydropyrido[3",2":4,5]thieno[3,2-e][1,4]diazepine-2(1H),5-diones

The reactions of N-(2-chloroacetyl)--amino acids with 3-cyanopyridine-2(1H)-thiones afforded N-(3-aminothieno[2,3-b]pyridin-2-ylcarbonyl)--amino acids. Heating of the latter smoothly produced 3,4-dihydropyrido[3",2":4,5]thieno[3,2-e][1,4]diazepine-2(1H),5-diones in high yields.     

A CAS SCF study of reactive interactions between Be(3 P) and H2(1ε g + )

Summary TheC _2v symmetry section of the Be(³ P)+ H₂(¹ _g ⁺ ) adiabatic energy surface is investigated by using the CAS SCF method. The small active space CAS SCF calculations in the valence approximation are followed by a perturbation treatment of the dynamic, core, and core-valence contributions in the framework of the CASPT2 method. The possibility of the nonradiative chemical deactivation of the lowest triplet state of Be by the insertion mechanism is studied. The structure of the³ B ₂ reaction intermediate BeH₂ is established. The calculations show that the symmetric dissociation of this intermediate into Be(¹ S) and 2H(² S) does not involve any barrier beyond the endothermicity of the corresponding reaction. The hydrogen abstraction mechanism via a linear configuration is shown to possess the activation barrier of about 25 mH.     

Chiral β-hydroxycarbonyl compounds based on (−)-menthone: structure and behavior in liquid crystalline systems

It has been established by X-ray structural analysis that 2-(1-biphenyl-4-yl-1-hydroxy)methyl-p-menthan-3-one, one of the products of the reaction of (–)-menthone triisopropyloxytitanium enolate with 4-phenylbenzaldehyde, has a 1R,2S,4S,1S configuration. In crystals, this -hydroxyketone adopts a chair conformation with equatorial methyl and isopropyl groups and an axial 2-(1-biphenyl-4-yl-1-hydroxy)methyl substituent. Unlike the stereoisomeric compound with the 1R,2S,4S,1S configuration, the exocyclic fragment of which has an intramolecular >C=O...H-O- hydrogen bond in crystals and solutions, in the crystals of the 1R,2S,4S,1S ketol under study, molecules are linked by a network of cooperative -O-H...O-H...O-H... hydrogen bonds. Based on the results of molecular mechanics calculations and experimental data of¹H NMR and IR spectroscopy, conformations of molecules of this compound, which are in equilibrium in solution, have been characterized. Based on data on spatial structures of stereoisomeric -hydroxyketones and the character of H-bonds formed by these compounds, the characteristic features of the effect of these chiral alloying additives on the supramolecular structure and macroscopic properties of liquid crystalline systems have been interpreted.The results of a study of stereoselectivity of the reactions of different (–)-menthone enolates with aromatic aldehydes will be published later.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1247–1255, July, 1995.The work was supported by the Foundation for Basic Research of the State Science and Engineering Committee of Ukraine (Project No. 93-3.2/75).     

Darzens reaction as a convenient method for the synthesis of α-chloroketones, α-chloroepoxides,and symmetrically substituted dioxines

Summary TheDarzens reaction of dichloroacetophenone (DCAP) with substituted benzaldehydes has been studied. The structure of the products was shown to depend on the phenyl group substituents. Reaction of benzaldehyde, 4-bromo-, and 2,4-dichlorobenzaldehydes results in 1-phenyl-3-aryl-3-chloropropane-1,2-diones (2a–c), reaction ofpara- ormeta-nitrobenzaldehydes yields 1-phenyl-2-chloro-3-aryl-2,3-epoxypropane-1-ones (3a, b). Upon the introduction of an alkoxy group into the phenyl ring of benzaldexyde and/or dichloroacetophenone, symmetrically substituted dioxines were obtained (6a–c). The structure of the reaction products has been established by single crystal X-ray investigations.

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Darzens-Reaktion als bequemes Verfahren zur Synthese von -Chloroketonen, -Chloroepoxiden und symmetrisch substituierten Dioxinen

Zusammenfassung DieDarzens-Reaction von Dichloracetophenon (DCAP) mit substituierten Benzaldehyden wurde untersucht. Die Struktur der Produkte ist von den Substituenten an der Phenylgruppe abhängig. Die Umsetzung mit Benzaldehyd, 4-Brom- und 2,4-Dichlorbenzaldehyd liefert 1-Phenyl-3-aryl-3-chloropropan-1,2-dione (2a–c), die Reaktion vonpara- odermeta-Nitrobenzaldehyd 1-Phenyl-2-chloro-3-aryl-2,3-epoxipropan-1-one (3a,b). Durch Einführung einer Alkoxygruppe in den Phenylring des Benzaldehyds und/oder des Dichloracetophenons erhält man symmetrisch substituierte Dioxine (6a–c). Die Struktur der Reaktionsprodukte wurde mittels Röntgenstrukturanalyse bestätigt.

     

Simple synthesis of benzo[f] pyrrolizidine and benzo[g]indolizidine with the use of products of the reductive allylation of indole and quinoline

Benzo[f]pyrrolizidine and benzo[g]indolizidine were synthesized by hydroboration-oxidation-intramolecular cyclization of the corresponding products of the reductive -allylation of indole (2) and quinoline (6) with allylboranes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 11, pp. 2807–2809, November, 1996,     

Conformational peculiarities of a new heterocyclic dihydrothienothiopyranoisoxazole system

The crystalline and molecular structures of 3H-3a,4-dihydro-7-methylthieno[3,2:5,6]thiopyrano[4,3-c]isoxazole and 3H-3a,4-dihydro-3-isopropoxycarbonyl-3a,7-dimethylthieno[3,2:5,6]thiopyrano[4,3-c]isoxazole are determined by X-ray analysis. The effect of steric factors on intramolecular 1,3-dipolar cycloaddition is shown.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 302–304, February, 1995.This work was financially supported by the Russian Foundation for Basic Research (Project No. 93-03-18461).     

On the excited states ofp-quinones and an interpretation of the photocycloaddition ofp-quinones to alkenes

A theoretical investigation is made of the electronic states ofp-benzoquinone (PBQ), methyl substituted PBQ's and 1,4-naphthoquinone (NQ). In accord with experiment, the lowest triplet state of PBQ is calculated to be³ B _1g (n, *), while that for duroquinone (DQ) is³ B _3g (, *). The electron densities of these states are consistent with the hypothesis that³ n, * states lead to oxetan formation and³, * states to cyclobutanes. It is predicted that trimethyl PBQ might form both adducts, as the two states are calculated to be nearly degenerate.The photochemistry of NQ is more complex. The lowest excited triplet state is calculated to be ofn, * symmetry, in accord with experiment; however, several other states are predicted near in energy, and the photochemistry cannot be rationalized unambiguously.This work was supported in part by the National Research Council of Canada.     

Synthesis of polysubstituted 1,3-cyclohexadienes from β-branched α,β-alkenals and monoesters of ylidenemalonic acids

3-Methyl- and 3-phenyl-2-butenal react with monoesters of alkylidene-, alkenylidene-, and arylmethylenemalonic acids in the presence of piperidine as the catalyst to give esters of 4,6-disubstituted 1,3-cyclohexadienecarboxylic acids in 23–96% yields. Under the same conditions cyclohexylideneacetic aldehyde reacts with the monoesters of prenylidene- and benzylidenemalonic acid to afford mixtures of 1,8a-trans- and 1,8a-cis-isomers of 1-substituted alkyl 1,5,6,7,8,8a-hexahydronaphthalene-2-carboxylates, the ratios and configurations of which were determined by means of¹H NMR spectroscopy. In some cases the formation of cyclic dienes is impeded by the competing process of decarboxylation of acidic ylidenemalonates. The derivatives of 4,6-diphenyl-1,3-cyclohexadienecarboxylic acid were shown to be convenient precursors for the preparation ofmeta-terphenyls.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. I, pp. 154–161, January, 1996.     

Synthesis of 1-(3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranosyl)uracils via an α,β-unsaturated aldehydrohexose

Summary Mercuric catalyzed hydrolysis of acetylatedL-rhamnal1 gave the ,-unsaturated aldehyde2. 1,2,4-Triazole was coupled, in a Michael type addition reaction, to2 at C-3 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to give, after acetylation at the anomeric center, an anomeric mixture of 1,5-di-O-acetyl-3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranose (3). Reaction of3 with silylated 2,4-dihydroxypyrimidines4 in the presence of trimethylsilyl triflate as catalyst followed by deprotection with 33% methylamine in absolute ethanol afforded the corresponding nucleosides7 and8.

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Synthese von 1-(3-(1,2,4-Triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranosyl)uracilen über eine ,-ungesättigte Aldohexose

Zusammenfassung Die quecksilberkatalysierte Hydrolyse von acetyliertemL-Rhamnal1 ergab die ,-ungesättigten Aldehyde2. 1,2,3-Triazol wurde in Gegenwart von 1,8-Diazabicyclo[5.4.0]-7-undecen mittels einer Addition vom Michael-Typ an C-3 von2 gekoppelt und ergab dann nach Acetylierung am anomeren Zentrum eine anomere Mischung von 1,5-Di-O-acetyl-3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranose (3). Die Reaktion von3 mit silyliertem 2,4-Di-hydroxypyrimidinen4 in Gegenwart von Trimethylsilyltriflat in absolutem Ethanol ergab die entsprechenden Nucleoside7 und8.